In certain fields, there is a need for electronic chips comprising cavities of relatively large dimensions, formed in a stack of layers coating the chip substrate.
In particular, chips used in integrated photonics may comprise a substrate, for example, made of silicon, containing optical components, and a stack of layers, for example, insulating layers, coating the substrate. To connect an optical fiber external to the chip to the optical components of the substrate, it would be desirable to form in the stack of layers coating the substrate a cavity having sufficiently large dimensions to receive an end of the optical fiber, for example, a cavity having horizontal dimensions capable of reaching a few millimeters and a depth of several micrometers.
The manufacturing of a cavity having such dimensions may however raise various problems.